the working of the mind itself as the test of the truth 

 of the results of its work ; but Cartesianism differs 

 from the others by reason of this attempt to include 

 physical science within the scope of its inquiries. In 

 spite of the great abilities of Descartes the attempt 

 was a brilliant failure. Its most wide-reaching 

 generalisation was the theory of vortices, purporting 

 to explain the motions of the solar system ; an 

 explanation which Newton showed to be utterly 

 inconsistent with the observed appearances. On 

 the physical side, therefore, the philosophy led to 

 nothing, and its failure goes far to prove that the 

 Cartesian test of truth is not valid when applied to 

 science. Leaving the backwater of Cartesianism and 

 returning to the main stream of thought, we go back 

 to Bacon (1561-1626), who, writing somewhat 

 earlier than Descartes, had put into literary form the 

 new ideas about knowledge which were stirring men's 

 minds at the time. That absolute truth could be 

 ascertained, no serious thinker of the age seems to 

 have doubted. Just as Descartes held that the meta- 

 physical truths styled eternal have been established 

 by God, so Bacon held that the relations among 

 phenomena are fixed by divine decrees, and that it 

 is the function of science to discover those decrees. 

 In the preface to the " Instauratio Magna " we find 

 the pious aspiration, " May He graciously grant us to 

 write an apocalypse, or true vision, of the footsteps 

 of the Creator imprinted on His creatures." The aim 



